WO2019159981A1

WO2019159981A1 - Cover glass, and in-cell liquid crystal display device

Info

Publication number: WO2019159981A1
Application number: PCT/JP2019/005142
Authority: WO
Inventors: 小池　章夫; 洋介竹田; 康成齋藤; 池田　徹; 貴章村上; 真府川
Original assignee: Ａｇｃ株式会社
Priority date: 2018-02-16
Filing date: 2019-02-13
Publication date: 2019-08-22
Also published as: CN111727177A; JP2021070590A; CN111727177B

Abstract

The purpose of the present invention is to provide: a cover glass which can be prevented from becoming cloudy, without an increase in the thickness thereof and the number of steps for production thereof, and which also has superior impact resistance; and an in-cell liquid crystal display device. The present invention pertains to a cover glass comprising: a chemically strengthened glass including a first main surface and a second main surface; and a fingerprint-resistant treatment layer provided on the first main surface, wherein of all alkali metals contained in a tensile stress layer of the chemically strengthened glass, the number of moles of Li is the largest, the DOL thereof is 60 μm or more, and the surface of the fingerprint-resistant treatment layer has a triboelectric charge amount of -1.5 to 0 kV.

Description

Cover glass and in-cell type liquid crystal display device

The present invention relates to a cover glass and an in-cell type liquid crystal display device.

An electronic device having a liquid crystal display device such as a smartphone may be equipped with a touch function. The touch function referred to here is a function for inputting information when an operator makes a finger touch or approach a cover glass provided on the surface of the display device.
As a structure for realizing a touch function, there is an external type (out-cell type) in which a touch panel is attached to a liquid crystal display device.
Since the external type can be used even if one of the liquid crystal display device and the touch panel is defective, the yield is excellent, but there is a problem that the thickness and weight increase.
Therefore, an on-cell type liquid crystal display device in which a touch panel is sandwiched between a liquid crystal element of a liquid crystal display device and a polarizing plate has appeared.
Further, an in-cell type liquid crystal display device in which an element having a touch function is embedded in a liquid crystal element has been developed as a thinner and lighter structure than the on-cell type.

On the other hand, the in-cell type liquid crystal display device (especially IPS liquid crystal display device) has a problem that when the cover glass is touched with a finger, the liquid crystal screen becomes partially cloudy due to charging. In the external type and the on-cell type, the touch panel located closer to the operator than the liquid crystal element contributes to static elimination, while the in-cell type liquid crystal display device does not include the touch panel closer to the operator than the liquid crystal element. This is because the liquid crystal element is easily charged with static electricity. In particular, a layer for improving impact resistance and antifouling properties may be formed on the surface of the cover glass. If these layers are easily charged, white turbidity is likely to occur.

Therefore, in an in-cell type liquid crystal display device, a structure is proposed in which a conductive layer is provided on the operator side of the liquid crystal display device to prevent white turbidity by releasing static electricity (Patent Document 1).

International Publication No. 2014/069377

However, the structure of Patent Document 1 has a problem that the thickness is increased by providing a conductive layer. There is also a problem that the number of steps for manufacturing the display device increases.

The present invention has been made in view of the above problems, and can prevent white turbidity without increasing the thickness and man-hours for manufacturing, and can provide a cover glass excellent in impact resistance, and an in-cell type liquid crystal display device ( In particular, an object is to provide an IPS liquid crystal display device.

The cover glass of the present invention includes a chemically strengthened glass having a first main surface and a second main surface, and a fingerprint prevention treatment layer provided on the first main surface of the chemically strengthened glass, The chemically strengthened glass has the largest number of moles of Li among all alkali metals contained in the tensile stress layer, the depth DOL of the compressive stress layer is 60 μm or more, and the triboelectric charge amount on the surface of the anti-fingerprint treatment layer is , JIS L1094: 2014, it is 0 kV or less and -1.5 kV or more according to D method.

Since the cover glass of the present invention has a triboelectric charge amount of 0 kV or less and −1.5 kV or more on the surface of the anti-fingerprint treatment layer, it is difficult to be triboelectrically charged even if a user's finger touches the surface. When incorporated, it can prevent white turbidity caused by static electricity.
In addition, since the cover glass of the present invention suppresses frictional electrification due to the physical properties of the cover glass, it is not necessary to provide a conductive layer, and white turbidity can be prevented without increasing the thickness and man-hour.
Further, in the cover glass of the present invention, the chemically strengthened glass has the largest number of moles of Li among all alkali metals contained in the tensile stress layer. Therefore, the compressive stress layer can contain more K and Na having a larger ion radius than Li during chemical strengthening, and the surface compressive stress of the compressive stress layer can be increased.
In the cover glass of the present invention, since the chemically strengthened glass has a depth DOL of the compressive stress layer of 60 μm or more, when an impact is applied from the outside, deformation due to the impact is difficult to be transmitted to the tensile stress layer, Increases sex.

In the cover glass of the present invention, the chemically strengthened glass is composed of A mol%, Al ₂ O ₃ with a total concentration of Li ₂ O, Na ₂ O, and K ₂ O among oxide components constituting the tensile stress layer. When the concentration is B mol%, it is preferable that A is 14.5 or more and A × B is 120 or more.
Alternatively, among the oxide components constituting the tensile stress layer, when the total concentration of Li ₂ O, Na ₂ O, and K ₂ O is C mass% and the concentration of Al ₂ O ₃ is D mass%, C is 11 or more and C × D is preferably 140 or more.
In this case, Li ₂ O, Na ₂ O, and K ₂ O, which do not contribute to the formation of the glass skeleton and have high mobility and are combined with static electricity to perform static elimination, contain a certain amount or more, so that the user's finger or the like touches the surface. Even so, it is less likely to be triboelectrically charged.
In this case, since a certain amount or more of Al ₂ O ₃ that contributes to skeleton formation and tends to be close to Li ₂ O, Na ₂ O, and K ₂ O is also included, Li ₂ O, Na ₂ O, K ₂ O enters between the skeletons formed of Al ₂ O ₃ to extend the distance. Therefore, Li ₂ O, Na ₂ O, and K ₂ O are more easily moved, and even if the user's finger or the like comes into contact with the surface, it is less likely to be frictionally charged.

In the cover glass of the present invention, the chemically strengthened glass has a total concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ of 81 mol% among the oxide components constituting the tensile stress layer. It is preferable that:
Alternatively, the tensile of the oxide components constituting the stress _{_{_{_{layer, SiO 2, Al 2 O 3}}}} , B 2 O 3, P 2 O total concentration of ₅ is preferably not less 82% by mass.
In this case, the concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ , which is a component having a low mobility and a weak effect of removing static electricity due to static electricity, contributes to the formation of the glass skeleton. Since it is suppressed below a certain level, even if the user's finger or the like comes into contact with the surface, it is more difficult to be triboelectrically charged.

The cover glass of the present invention preferably includes at least one of an antiglare function layer or an antireflection layer provided between the chemically strengthened glass and the anti-fingerprint treatment layer.
When the cover glass of the present invention includes an antiglare function layer, it can scatter incident light and blur the reflection due to incident light. When the cover glass of the present invention includes an antireflection layer, reflection of incident light can be prevented and reflection due to incident light can be prevented.

The cover glass of the present invention preferably includes a light shielding layer provided on the second main surface.
When the light shielding layer is provided on the second main surface, when the cover glass is incorporated in the display device, the wiring on the display device side is concealed or the illumination light of the backlight is concealed from the periphery of the display device. It is possible to prevent the illumination light from leaking.

When the cover glass of the present invention includes a light shielding layer provided on the second main surface, the light shielding layer preferably has an opening, and the opening has an infrared transmittance higher than that of the light shielding layer. A high infrared transmission layer is preferably provided.
In the case where an infrared transmission layer is provided in the light shielding layer, the infrared sensor can be provided on the back side of the light shielding layer and the infrared transmission layer can be made inconspicuous when a cover glass is incorporated in a display device having an infrared sensor.

In the cover glass of the present invention, the chemically strengthened glass is preferably bent glass.
When the chemically strengthened glass is bent glass, even if the counterpart member to which the cover glass is attached has a bent shape, there is no possibility that the mounting accuracy will be lowered.

The cover glass of the present invention comprises an anti-glare layer between the first main surface and the anti-fingerprint treatment layer, and the anti-glare layer has a surface roughness Ra of 0.01 μm to 0.5 μm. preferable.
In this case, visibility can be ensured while preventing charging.

The in-cell type IPS liquid crystal display device of the present invention includes any one of the above cover glasses.
According to the present invention, an in-cell IPS liquid crystal display device protected by a cover glass can be obtained.

FIG. 1 is a cross-sectional view of a cover glass according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a cover glass according to a modification. FIG. 3 is a cross-sectional view of a cover glass according to a modification. 4A is a perspective view of a cover glass according to a modified example, and FIG. 4B is a cross-sectional view taken along the line BB of FIG. 4A. FIG. 5 is a cross-sectional view of a cover glass according to a modification. FIG. 6 is a partial cross-sectional view of a display device including a cover glass according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In addition, when the range is expressed as “a to b” in the present specification, the range is a to b and is interpreted to mean a range including the lower limit value a and the upper limit value b.
[Composition of cover glass]
First, the configuration of the cover glass will be described.
A cover glass 1 shown in FIG. 1 includes a chemically strengthened glass 2 and a fingerprint prevention treatment layer 81.

The chemically strengthened glass 2 has a rectangular shape in plan view and transmits visible light. The chemically strengthened glass 2 includes a first main surface 21, a second main surface 22, and an end surface 23. A chamfered portion 24 is provided on the end surface 23.

The chemically strengthened glass 2 includes compressive stress layers 25 and 32 and a tensile stress layer 27. The compressive stress layers 25 and 32 are layers on which a compressive stress acts (a layer having a compressive stress of 0 MPa or more). The compressive stress layer 25 is provided on the surface on the first main surface 21 side, and the compressive stress layer 32 is provided on the surface on the second main surface 22 side. Although the compressive stress layer is also provided on the end face 23, description thereof is omitted here.
The tensile stress layer 27 is a layer on which a tensile stress acts (a layer having a compressive stress of less than 0 MPa). The tensile stress layer 27 is provided between the compressive stress layer 25 and the compressive stress layer 32.

Among the total alkali metals contained in the tensile stress layer 27 of the chemically strengthened glass 2, the number of moles of Li is the largest. Due to the composition having the largest number of moles of Li, the compressive stress layers 25 and 32 can contain more K and Na having a larger ion radius than Li during chemical strengthening. The number of moles of Li is more preferably 0.5 times or more, more preferably 0.8 or more, relative to the number of moles of Na.

The depth DOL (Depth of Layer) of the compressive stress layers 25 and 32 of the chemically strengthened glass 2 is 60 μm or more. When the DOL is 60 μm or more, when an impact is applied from the outside, the deformation due to the impact becomes difficult to be transmitted to the tensile stress layer, and the impact resistance of the glass surface can be improved.
The DOL is more preferably 80 μm to 250 μm.
DOL theoretically means the depth from the surface to the position where the compressive stress is 0 MPa in the plate thickness direction, but the alkali in the depth direction of the glass by EPMA (electron probe micro analyzer, electron beam microanalyzer). An ion concentration analysis (concentration analysis of ions diffused by chemical strengthening in this example) is performed, and the ion diffusion depth obtained by measurement can be regarded as DOL. The DOL can also be measured using a surface stress meter (for example, FSM-6000 manufactured by Orihara Seisakusho).

Of the oxide components constituting the tensile stress layer of the chemically strengthened glass 2, when the total concentration of Li ₂ O, Na ₂ O, K ₂ O is A mol% and the concentration of Al ₂ O ₃ is B mol% A is preferably 14.5 or more and A × B is 120 or more. More preferably, A is 15 to 20, and A × B is 170 to 300.

In addition, when expressing A by mass (when the total concentration of Li ₂ O, Na ₂ O, and K ₂ O among oxide components constituting the tensile stress layer is C mass%), Li ₂ O, Depending on the molar ratio of each component to the total of Na ₂ O and K ₂ O, C is preferably 11 or more, more preferably 12 to 20.
When A × B is expressed by mass (among the oxide components constituting the tensile stress layer, the total concentration of Li ₂ O, Na ₂ O, K ₂ O is C mass%, and the concentration of Al ₂ O ₃ is D If the weight percent represented by C × D) _{_{also, Li 2 O, Na 2 O}} , depending on the molar ratio of each component to the sum of _{K 2} O, C × D is preferably 140 or more, 150-400 Gayori preferable.
The reason is as follows.

Components constituting glass can be broadly classified into components that contribute to glass skeleton formation (also referred to as network formers) and components that do not contribute to skeleton formation.
Among these, from the viewpoint of preventing charging, it is preferable that there are many components that do not contribute to skeleton formation. This is because the component that does not contribute to the skeleton formation has higher mobility than the contributing component, and is considered to perform static elimination in combination with static electricity. Since Li ₂ O, Na ₂ O, and K ₂ O are components that do not contribute to skeleton formation in glass, the content of these components is preferably large, that is, the above-described A and C are preferably large. This is the basis for defining A.
Further, Al ₂ O ₃ behaves as a component that contributes to skeleton formation and a component that does not contribute. When Al ₂ O ₃ contributes to skeleton formation, it tends to be close to Li ₂ O, Na ₂ O, and K ₂ O. When al ₂ O ₃ is _Li 2 _O, Na 2 O, close to the _{_{_{K 2 O, Li 2 O,}}} Na 2 O, K 2 O is enters between the components forming the skeleton, to extend the distance between the backbone . Extending the distance between the skeletons is preferable because components that do not contribute to the skeleton formation easily move between the skeletons and the mobility increases. This is the reason for defining A × B.

The triboelectric charge is a phenomenon that occurs on the surface of the compressive stress layer 25. The reason for defining a preferred composition of the tensile stress layer 27 is as follows.
Since it is the skeleton of the glass that affects the triboelectric charge, it is originally desirable to define the glass structure. However, since glass is amorphous and it may be difficult to specify the structure, it is preferable to define it by composition. On the other hand, since the compressive stress layer 25 is subjected to ion exchange by chemical strengthening, the composition is different from that of the tensile stress layer 27, but the network structure of glass is the same. If a glass having the same composition as the composition of the compressive stress layer 25 is manufactured without chemical strengthening, the network structure is different. Therefore, it is difficult to specify the structure of the compressive stress layer 25 by the composition of the compressive stress layer 25. Therefore, by specifying the composition of the tensile stress layer 27, the structure of the tensile stress layer 27 is specified, and the structure of the tensile stress layer 27 and the compressive stress layer 25 does not change even when chemically strengthened. The structure of the compressive stress layer 25 is specified from the composition of the stress layer 27.

Of the oxide components constituting the tensile stress layer 27 of the chemically strengthened glass 2, the total concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ is preferably 81 mol% or less. This is because these elements are components that contribute to the formation of a glass skeleton, and the smaller the content, the more components that contribute to static elimination. In addition, the smaller the content of these components, the wider the distance between the components forming the skeleton, and the higher the mobility of the components that do not contribute to the skeleton formation.
The triboelectric charge is a phenomenon that occurs on the surface of the compressive stress layer 25, but the reason for defining the preferred composition of the tensile stress layer is the same as the reason for defining A and A × B.

In _the case that is the total concentration of _{_{_{_{SiO 2, Al 2 O 3,}}}} B 2 O 3, P 2 O 5 in wt%, depending on the molar ratio of the components for these total content of these components The total amount is preferably 82% by mass or less, and more preferably 70% by mass to 81% by mass.

More specifically, the composition of the tensile stress layer 27 is expressed in terms of mass percentage on the basis of oxide, and SiO ₂ is 55% to 68%, Al ₂ O ₃ is 10% to 25%, and B ₂ O ₃ is 0%. ~ 5%, P ₂ O ₅ 0% ~ 15%, Li ₂ O 0% ~ 8%, Na ₂ O 1% ~ 20%, K ₂ O 0.1% ~ 10%, M
gO 0% to 10%, CaO 0% to 5%, SrO 0% to 5%, BaO 0% to 5%, ZnO 0% to 5%, TiO ₂ 0% to 1%, ZrO ₂ from 0% to 5%, and _Fe 2 _{O 3} glass composition containing 0.005% to 0.1% is preferred.
The composition of the tensile stress layer 27 can be quantified by a known composition analysis method such as chemical analysis, spectrophotometric analysis, atomic absorption analysis, or fluorescent X-ray analysis. The measurement position may be an arbitrary position of the tensile stress layer 27, but is preferably the center position in the thickness direction of the glass substrate and the center of gravity on the plane.

Each component in the preferable glass composition of the tensile stress layer 27 described above will be described below. In the following description of the glass composition, unless otherwise noted, the content expressed in% means the content in terms of oxide based mass percentage.

SiO ₂ is a component constituting the skeleton of glass. SiO ₂ is a component that increases chemical durability, and is a component that reduces the occurrence of cracks when a scratch (indentation) is made on the glass surface. In order to suppress the occurrence of cracks, the SiO ₂ content is preferably 55% or more, more preferably 56% or more, further preferably 56.5% or more, and particularly preferably 58% or more. On the other hand, in order to improve the mobility of elements contributing to static elimination in the glass and to improve the meltability in the glass production process, the SiO ₂ content is preferably 68% or less, more preferably 65% or less, More preferably, it is 63% or less, Most preferably, it is 61% or less.

Al ₂ O ₃ is an effective component for improving the ion exchange performance during the chemical strengthening treatment and increasing the surface compressive stress CS after the chemical strengthening. Al ₂ O ₃ has an effect of improving the fracture toughness value of glass. Further, Al ₂ O ₃ is a component that increases the Tg of the glass and is also a component that increases the Young's modulus. Furthermore, Al ₂ O ₃ also has an effect of improving the mobility of elements that contribute to static elimination in glass. In order to enhance these properties, the Al ₂ O ₃ content is preferably 10% or more, and more preferably 12% or more. In order to increase the fracture toughness value, the Al ₂ O ₃ content is more preferably 14% or more. On the other hand, the content of Al ₂ O ₃ is preferably 25 from the viewpoint of increasing the content of elements contributing to static elimination in the glass and maintaining the acid resistance of the glass and lowering the devitrification temperature. % Or less, more preferably 23% or less.

Al ₂ O ₃ is a constituent component of the lithium aluminosilicate crystal. In order to suppress crystal precipitation during bending, the content of Al ₂ O ₃ is preferably 22% or less, more preferably 20% or less, and even more preferably 19% or less.

B ₂ O ₃ is a component that improves the meltability of the glass. B ₂ O ₃ is also a component that improves the chipping resistance of the glass. B ₂ O ₃ is not essential, but the content in the case of inclusion is preferably 0.1% or more, more preferably 0.5% or more, and further preferably 1% or more in order to improve the meltability. is there. On the other hand, the content of B ₂ O ₃ is preferably 5% or less from the viewpoint of improving the mobility of elements contributing to static elimination in glass and preventing the occurrence of striae during melting. Preferably it is 4% or less, More preferably, it is 3% or less, Most preferably, it is 2.5% or less.

P ₂ O ₅ is a component that improves ion exchange performance and chipping resistance during chemical strengthening treatment. P ₂ O ₅ is not essential, but the content in the case of inclusion is preferably 0.1% or more, more preferably 1% or more, and further preferably 2% or more. On the other hand, in order to ensure acid resistance and prevent charging, the content of P ₂ O ₅ is preferably 15% or less, more preferably 10% or less, still more preferably 8% or less, and even more preferably 6% or less. Especially preferably, it is 4% or less.

Li ₂ O is a component that forms a surface compressive stress layer by chemical strengthening treatment with a sodium salt such as sodium nitrate. Li ₂ O is also a substance that contributes to static elimination in the glass.
The content of Li ₂ O is preferably 0.1% or more in order to obtain the effect of inclusion, more preferably 1% or more, and further preferably 2% or more. On the other hand, from the viewpoint of ensuring weather resistance, the Li ₂ O content is preferably 8% or less. Further, in order to suppress crystal precipitation during bending, the Li ₂ O content is preferably 7% or less, and more preferably 6% or less.

Na ₂ O is a component that forms a surface compressive stress layer in a chemical strengthening treatment using a potassium salt, and is a component that can improve the meltability of glass. Na ₂ O is also a substance that contributes to static elimination in the glass.
In order to obtain the effect, the content of Na ₂ O is preferably 1% or more, more preferably 1.5% or more, and further preferably 2% or more. On the other hand, in order to improve the surface compressive stress CS, the content of Na ₂ O is preferably 20% or less, more preferably 16% or less, further preferably 14% or less, and particularly preferably 8% or less.

K ₂ O is a substance that improves the meltability of glass. K ₂ O is also a substance that contributes to static elimination in the glass. When K ₂ O is contained, the content is preferably 0.1% or more, and more preferably 0.5% or more. On the other hand, from the viewpoint of ensuring the friability of chemically strengthened glass, the content of K ₂ O is preferably 8% or less, more preferably 5% or less, and even more preferably 3% or less.

MgO is not essential, but is preferably contained in order to increase the surface compressive stress CS of the chemically strengthened glass. MgO has the effect of improving the fracture toughness value. Therefore, the content of MgO is preferably 0.1% or more, more preferably 0.5% or more, and further preferably 2% or more. On the other hand, in order to suppress devitrification at the time of glass melting, the content of MgO is preferably 10% or less, more preferably 8% or less, and further preferably 6% or less.

CaO is not essential, but is a component that improves the meltability of the glass and may be contained. The content when CaO is contained is preferably 0.05% or more, more preferably 0.1% or more, and further preferably 0.15% or more. On the other hand, from the viewpoint of ensuring the ion exchange performance during the chemical strengthening treatment, the CaO content is preferably 3.5% or less, more preferably 2.0% or less, and even more preferably 1.5% or less.

SrO is not essential, but is a component that improves the meltability of the glass and may be contained. When SrO is contained, the content is preferably 0.05% or more, more preferably 0.1% or more, and further preferably 0.5% or more. On the other hand, in order to increase the ion exchange performance during the chemical strengthening treatment, the content of SrO is preferably 5% or less, more preferably 3.5% or less, further preferably 2% or less, and substantially no content. Particularly preferred.

BaO is not essential, but is a component that improves the meltability of the glass, and may be contained. The content when BaO is contained is preferably 0.1% or more, more preferably 0.5% or more, and further preferably 1% or more. On the other hand, in order to increase the ion exchange performance during the chemical strengthening treatment, the content of BaO is preferably 5% or less, more preferably 3% or less, still more preferably 2% or less, and still more preferably not contained. .

ZnO is a component that improves the meltability of the glass and may be contained. Content in the case of containing ZnO becomes like this. Preferably it is 0.05% or more, More preferably, it is 0.1% or more. On the other hand, if the ZnO content is 5% or less, the weather resistance of the glass can be increased, which is preferable. The content of ZnO is more preferably 3% or less, still more preferably 1% or less, and particularly preferably not contained.

TiO ₂ is a component that suppresses the color tone change of the glass due to solarization, and may be contained. The content in the case of containing TiO ₂ is preferably 0.01% or more, more preferably 0.03% or more, still more preferably 0.05% or more, and particularly preferably 0.1% or more. On the other hand, in order to suppress devitrification at the time of melting, the content of TiO ₂ is preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.2% or less.

ZrO ₂ is a component that increases the surface compressive stress CS due to ion exchange during the chemical strengthening treatment, and may be contained. When ZrO ₂ is contained, the content is preferably 0.1% or more, more preferably 0.5% or more, and further preferably 1% or more. On the other hand, in order to suppress devitrification at the time of melting and improve the quality of chemically strengthened glass, the content of ZrO ₂ is preferably 5% or less, more preferably 3% or less, and particularly preferably 2.5%. It is as follows.

Since Fe ₂ O ₃ absorbs heat rays, it has an effect of improving the solubility of the glass, and it is preferably contained when the glass is mass-produced using a large melting furnace. In that case, the content is preferably 0.005% or more, more preferably 0.006% or more, and still more preferably 0.007% or more. On the other hand, since coloring occurs when the content is excessive, the content of Fe ₂ O ₃ is preferably 0.1% or less, more preferably 0.05% or less, and still more preferably 0.8% in order to increase the transparency of the glass. It is 02% or less, particularly preferably 0.015% or less.
Here, all the iron oxides in the glass have been described as Fe ₂ O ₃ , but in actuality, it is common that Fe (III) in the oxidized state and Fe (II) in the reduced state are mixed. . Among these, Fe (III) produces yellow coloration, Fe (II) produces blue coloration, and a green coloration occurs on the glass in a balance between the two.

A chemically tempered glass _{_{_{_{2 Y 2 O 3, La 2}}}} O 3, Nb 2 O 5 may be contained. The total content when these components are contained is preferably 0.01% or more, more preferably 0.05% or more, still more preferably 0.1% or more, and particularly preferably 0.15. % Or more, most preferably 1% or more. On the other hand, if the content of Y ₂ O ₃ , La ₂ O ₃ , and Nb ₂ O ₅ is too large, the glass tends to be devitrified at the time of melting, and the quality of the chemically strengthened glass may be lowered. The total amount is preferably 7% or less. The total content of Y ₂ O ₃ , La ₂ O ₃ , and Nb ₂ O ₅ is more preferably 6% or less, further preferably 5% or less, particularly preferably 4% or less, and most preferably 3.5%. % Or less.

Ta ₂ O ₅ and Gd ₂ O ₃ may be contained in a small amount in order to improve the crushability of the chemically strengthened glass. However, since the refractive index and the reflectance are increased, the total content thereof is 5% or less. Preferably, it is more preferably 2% or less, and further preferably not contained.

Furthermore, when coloring glass, a coloring component may be added within a range that does not hinder achievement of desired chemical strengthening properties. Examples of the coloring component include Co ₃ O ₄ , MnO ₂ , NiO, CuO, Cr ₂ O ₃ , V ₂ O ₅ , Bi ₂ O ₃ , SeO ₂ , CeO ₂ , Er ₂ O ₃ , Nd ₃ O _{3 and the} like. Are mentioned as preferred.
The total content of the coloring components is preferably 7% or less because problems such as devitrification hardly occur. This content is preferably 5% or less, more preferably 3% or less, and even more preferably 2% or less. When giving priority to the visible light transmittance of glass, it is preferable that these components are not substantially contained.

As a fining agent for melting the glass, SO ₃ , chloride, fluoride and the like may be appropriately contained. Since As ₂ O ₃ has a large environmental load, it is preferable not to contain it. When Sb ₂ O ₃ is contained, it is preferably 1% or less, more preferably 0.5% or less, and most preferably not contained.

The surface compressive stress CS of the chemically strengthened glass 2 is preferably 300 MPa to 1500 MPa.
When CS is 300 MPa or more, the bending strength necessary for the cover glass can be maintained. When CS is 1500 MPa or less, it can be prevented from being shattered when broken. CS is more preferably 800 MPa to 1200 MPa.
Here, the surface compressive stress CS means the compressive stress on the outermost surface of the glass. The surface compressive stress CS can be measured using a surface stress meter (for example, FSM-6000 manufactured by Orihara Seisakusho).

The internal tensile stress CT of the chemically strengthened glass 2 is preferably 20 MPa to 100 MPa.
When CT is 20 MPa or more, it is possible to achieve a state in which the compressive stress existing as a reaction has an appropriate stress value and depth. When CT is 100 MPa or less, scattering can be prevented when broken. CT is more preferably 40 MPa to 85 MPa.
The internal tensile stress CT is approximately obtained by the relational expression CT = (CS × DOL) / (t−2 × DOL), where t is the thickness of the cover glass 1.

The fingerprint prevention treatment layer 81 is a layer that reduces the adhesion of dirt due to fingerprints, sebum, sweat, and the like when a human finger touches the first main surface 21.

The constituent material of the fingerprint prevention treatment layer 81 can be appropriately selected from fluorine-containing organic compounds that can impart antifouling properties, water repellency, and oil repellency. Specific examples include fluorine-containing organic silicon compounds and fluorine-containing hydrolyzable silicon compounds. The fluorine-containing organic compound can be used without particular limitation as long as it can impart antifouling properties, water repellency and oil repellency.
Note that the fluorine-containing organic compound originally has a characteristic of being easily charged when touched with a finger when formed on chemically strengthened glass. In this embodiment, the triboelectric charge amount on the surface of the fingerprint prevention treatment layer 81 is 0 kV. Hereinafter, since it is −1.5 kV or more, charging can be suppressed.

The fluorine-containing organosilicon compound film forming the fingerprint prevention treatment layer 81 is formed on the first main surface 21 of the chemically strengthened glass 2. Alternatively, when an antiglare layer is formed on the first main surface 21 and an antireflection layer is formed on the surface, it is preferable that an anti-fingerprint treatment layer 81 is formed on the surface of the antireflection layer. In addition, when a glass substrate on which the first main surface 21 of the chemically strengthened glass 2 is subjected to a surface treatment such as an antiglare treatment and an antireflection layer is not used, the fluorine-containing organosilicon compound coating is used for these surface treatments. It is preferable to be formed directly on the surface provided with.

The fluorine-containing hydrolyzable silicon compound used for forming the fluorine-containing organic silicon compound film is not particularly limited as long as the resulting fluorine-containing organic silicon compound film has antifouling properties such as water repellency and oil repellency. Specific examples include fluorine-containing hydrolyzable silicon compounds having one or more groups selected from the group consisting of perfluoropolyether groups, perfluoroalkylene groups, and perfluoroalkyl groups.

Specific examples of materials for forming the anti-fingerprint treatment layer 81 include “KP-801” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and “X-71” (trade name, Shin-Etsu Chemical) that are commercially available. Kogyo Co., Ltd.), "KY-130" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), "KY-178" (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), "KY-185" (trade name, Shin-Etsu Chemical) Chemical Industry Co., Ltd.), “KY-195” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), “OPTOOL (registered trademark)”, DSX (trade name, manufactured by Daikin Industries, Ltd.), etc. It is also possible to add oils and antistatic agents to commercially available products.

The layer thickness of the anti-fingerprint treatment layer 81 is not particularly limited, but is preferably 2 nm to 20 nm, more preferably 2 nm to 15 nm, and further preferably 3 nm to 10 nm. When the layer thickness is 2 nm or more, the surface of the antireflection layer is uniformly covered by the anti-fingerprint treatment layer 81, and the anti-fingerprint and abrasion resistance can withstand practical use. Further, when the layer thickness is 20 nm or less, the optical characteristics such as luminous reflectance and haze value in the state where the anti-fingerprinting treatment layer 81 is laminated are good.

The triboelectric charge amount on the surface of the fingerprint prevention treatment layer 81 of the cover glass 1 is 0 kV or less and −1.5 kV or more. The triboelectric charge amount here means the triboelectric charge amount obtained by the D method (friction charge attenuation measuring method) described in JIS L1094: 2014. Although the fluorine-based anti-fingerprint treatment layer is negatively charged in the above evaluation method, it can be prevented from being charged when it is −1.5 kV or more.
The triboelectric charge amount is more preferably 0 kV to −1 kV.
The above is the description of the configuration of the cover glass 1.

[Production method of cover glass 1]
Next, an example of a method for manufacturing the cover glass 1 will be described.

First, the chemically strengthened glass 2 is manufactured.
The chemically strengthened glass 2 is manufactured by chemically strengthening glass for chemical strengthening manufactured by a general glass manufacturing method.
A chemical strengthening process is a process which performs the ion exchange process on the surface of glass, and forms the surface layer which has a compressive stress. Specifically, an ion exchange treatment is performed at a temperature below the glass transition point of the chemically strengthened glass, and metal ions (typically Li ions or Na ions) having a small ion radius near the glass plate surface, Substitution with ions having a larger ionic radius (typically Na ions or K ions for Li ions and K ions for Na ions).

The chemically strengthened glass 2 can be produced, for example, by chemically strengthening glass for chemical strengthening having the composition of the tensile stress layer 27 described above.
In addition, the following manufacturing method is an example in the case of manufacturing plate-shaped chemically strengthened glass.

First, glass raw materials are prepared and heated and melted in a glass melting furnace. Thereafter, the glass is homogenized by bubbling, stirring, adding a clarifying agent, etc., formed into a glass plate having a predetermined thickness by a conventionally known forming method, and slowly cooled. Or you may shape | mold into a plate shape by the method of cut | disconnecting, after shape | molding in a block shape and gradually cooling.

Examples of the method for forming into a plate shape include a float method, a press method, a fusion method, and a downdraw method. In particular, when a large glass plate is produced, the float method is preferable. Further, continuous molding methods other than the float method, for example, a fusion method and a downdraw method are also preferable.

Thereafter, the molded glass is cut into a predetermined size and chamfered. It is preferable to chamfer so that the dimension of the chamfered portion 24 in a plan view is 0.05 mm or more and 0.5 mm or less.

Next, the glass plate is subjected to ion exchange treatment once or twice (about one step or two steps) to perform chemical strengthening, and the compressive stress layers 25 and 32 and the tensile stress layer 27 are formed.
In the chemical strengthening step, a glass to be treated is a molten salt containing an alkali metal ion having a larger ionic radius than an alkali metal ion (for example, sodium ion or lithium ion) contained in the glass (for example, potassium salt, Or a sodium salt) is made to contact in the temperature range which does not exceed the transition temperature of glass.

The alkali metal ions in the glass and the alkali metal ions having a large ion radius of the alkali metal salt are ion-exchanged, and a compressive stress is generated on the glass surface due to the difference in the occupied volume of the alkali metal ions to form a compressive stress layer. . Although the temperature range which makes glass contact with molten salt should just be a temperature range which does not exceed the transition temperature of glass, it is preferable that it is 50 degrees C or less from a glass transition point. Thereby, stress relaxation of the glass can be prevented.

In the chemical strengthening treatment, the treatment temperature and treatment time for bringing the glass into contact with the molten salt containing alkali metal ions can be appropriately adjusted according to the composition of the glass and the molten salt. The temperature of the molten salt is usually preferably 350 ° C. or higher, more preferably 370 ° C. or higher, usually 500 ° C. or lower, more preferably 450 ° C. or lower.

By setting the temperature of the molten salt to 350 ° C. or higher, it is possible to prevent chemical strengthening from becoming difficult due to a decrease in ion exchange rate. Moreover, decomposition | disassembly and deterioration of molten salt can be suppressed by making the temperature of molten salt into 500 degrees C or less.

The time for bringing the glass into contact with the molten salt is usually preferably 10 minutes or more and more preferably 15 minutes or more in order to give sufficient compressive stress per time. Moreover, in long-time ion exchange, productivity falls and the compressive stress value decreases due to relaxation. Therefore, the time for contacting the glass with the molten salt is usually 20 hours or less, preferably 16 hours or less. .

The number of times of chemical strengthening is exemplified once or twice, but the number of times is not particularly limited as long as the physical properties (DOL, CS, CT) of the target compressive stress layer and tensile stress layer can be obtained. It may be strengthened 3 times or more. Moreover, you may perform the heat processing process between 2 strengthening. In the following description, the case where the chemical strengthening is performed three times and the case where the heat treatment process is performed between the two strengthening steps are referred to as three-step strengthening.
The three-stage strengthening can be performed by, for example, strengthening processing method 1 or strengthening processing method 2 described below.

(Strengthening treatment method 1)
In the tempering treatment method 1, first, a glass for chemical strengthening containing Li ₂ O is brought into contact with a metal salt containing sodium (Na) ions (first metal salt), and Na ions in the metal salt, Ion exchange occurs with Li ions in the glass. Hereinafter, this ion exchange process may be referred to as “first stage process”.
In the first stage treatment, for example, the glass for chemical strengthening is immersed in a metal salt (for example, sodium nitrate) containing Na ions at about 350 ° C. to 500 ° C. for about 0.1 to 24 hours. In order to improve productivity, the treatment time for the first stage is preferably 12 hours or less, and more preferably 6 hours or less.

By the first step, a deep compressive stress layer is formed on the glass surface, and a stress profile can be formed such that CS is 200 MPa or more and the compressive stress depth DOL is 1/8 or more of the plate thickness. Moreover, since the glass of the stage which finished the process of the 1st step | stage has a large internal tensile stress CT, its crushability is large. However, it is preferable that the CT at this stage is large because the friability is improved by subsequent treatment. 90 MPa or more is preferable, as for the internal tensile stress CT of the glass which finished the process of the 1st step | paragraph, 100 MPa or more is more preferable, and 110 MPa or more is further more preferable. This is because the surface compressive stress CS of the compressive stress layer 25 increases.

The first metal salt is an alkali metal salt and contains the most Na ions as the alkali metal ions. Although the first metal salt may contain Li ions, Li ions are preferably 2% or less, more preferably 1% or less, and more preferably 0.2% or less with respect to 100% of the number of moles of alkali ions. preferable. The first metal salt may contain K ions. The K ion is preferably 20% or less and more preferably 5% or less with respect to 100% of the number of moles of alkali ions contained in the first metal salt.

Next, the glass after finishing the first step is brought into contact with a metal salt containing lithium (Li) ions (second metal salt), and ions of Li ions in the metal salt and Na ions in the glass are contacted. The compressive stress value near the surface layer is reduced by the exchange. This process may be referred to as “second stage process”.
Specifically, for example, a glass that has undergone the first stage treatment with a metal salt containing Na and Li at about 350 ° C. to 500 ° C. (for example, a mixed salt of sodium nitrate and lithium nitrate) is used for 0.1 to 24 hours. Soak for about an hour. In order to improve productivity, the treatment time for the second stage is preferably 12 hours or less, and more preferably 6 hours or less.

The glass after the second stage treatment can reduce the internal tensile stress and will not be severely cracked when broken.

The second metal salt is an alkali metal salt, and preferably contains Na ions and Li ions as alkali metal ions. The second metal salt is preferably nitrate. The total number of moles of Na ions and Li ions is preferably 50% or more, more preferably 70% or more, and more preferably 80% or more with respect to 100% of the number of moles of alkali metal ions contained in the second metal salt. preferable. The stress profile in DOL / 4 to DOL / 2 can be controlled by adjusting the Na / Li molar ratio.
The optimum value of the Na / Li molar ratio of the second metal salt varies depending on the glass composition, but is preferably 0.3 or more, more preferably 0.5 or more, and more preferably 1 or more. In order to increase the compressive stress value of the compressive stress layer while reducing the CT, it is preferably 100 or less, more preferably 60 or less, and even more preferably 40 or less.

When the second metal salt is a sodium nitrate-lithium nitrate mixed salt, the mass ratio of sodium nitrate to lithium nitrate is preferably, for example, 25:75 to 99: 1, more preferably 50:50 to 98: 2, 70 : 30 to 97: 3 is more preferable.

Next, the glass after finishing the second step is brought into contact with a metal salt containing potassium (K) ions (third metal salt), and ion exchange between K ions in the metal salt and Na ions in the glass is performed. Thus, a large compressive stress is generated on the glass surface. This ion exchange process may be referred to as a “third stage process”.
Specifically, for example, the glass after the second stage treatment is immersed in a metal salt (for example, potassium nitrate) containing K ions at about 350 to 500 ° C. for about 0.1 to 10 hours. By this process, a large compressive stress can be formed in the region of about 0 μm to 10 μm on the glass surface layer.

Since the third stage treatment increases only the compressive stress in the shallow part of the glass surface and hardly affects the inside, a large compressive stress can be formed on the surface layer while suppressing the internal tensile stress.
The third metal salt is an alkali metal salt and may contain Li ions as alkali metal ions, but Li ions are 2% with respect to 100% of the number of moles of alkali metal ions contained in the third metal salt. The following is preferable, 1% or less is more preferable, and 0.2% or less is more preferable. The Na ion content is preferably 2% or less, more preferably 1% or less, and still more preferably 0.2% or less.

Enhance process 1 is preferable because the total processing time of the first to third stages can be reduced to 24 hours or less, so that productivity is high. The total treatment time is more preferably 15 hours or less, and even more preferably 10 hours or less.

(Strengthening treatment method 2)
In the tempering treatment method 2, first, a chemically strengthening glass containing Li ₂ O is brought into contact with a first metal salt containing sodium (Na) ions, so that Na ions in the metal salt and Li in the glass are in contact with each other. A first stage process for causing ion exchange with ions is performed.
Since the first stage process is the same as that in the case of the reinforcement process method 1, the description thereof is omitted.

Next, it heat-processes, without making the glass which finished the process of the 1st step contact a metal salt. This is called the second stage process.
The second stage treatment is performed, for example, by holding the glass after the first stage treatment in the atmosphere at a temperature of 350 ° C. or higher for a certain period of time. The holding temperature is a temperature below the strain point of the glass for chemical strengthening, preferably 10 ° C. or less higher than the first stage processing temperature, and more preferably the same temperature as the first stage processing temperature.
According to this process, it is considered that the alkali ions introduced to the glass surface in the first stage process thermally diffuse to reduce the CT.

Next, the glass after finishing the second step is brought into contact with a third metal salt containing potassium (K) ions, and the glass surface is obtained by ion exchange between K ions in the metal salt and Na ions in the glass. A large compressive stress is generated. This ion exchange process may be referred to as a “third stage process”.
The third stage process is the same as that in the case of the strengthening process method 1, and the description thereof is omitted.

Enhance process 2 is preferable because the total processing time of the first to third stages can be reduced to 24 hours or less, so that productivity is high. The total treatment time is more preferably 15 hours or less, and even more preferably 10 hours or less.

According to the strengthening treatment method 1, the stress profile can be precisely controlled by adjusting the composition of the second metal salt used in the second stage treatment and the treatment temperature.
According to the tempering method 2, a chemically strengthened glass having excellent characteristics can be obtained at a low cost by a relatively simple treatment.

The treatment conditions for the chemical strengthening treatment may be appropriately selected in terms of time, temperature, etc. in consideration of the characteristics / composition of the glass and the type of molten salt.
The chemically strengthened glass 2 is manufactured by the above procedure.

Next, a fingerprint prevention treatment layer 81 is formed on the first main surface 21 of the chemically strengthened glass 2.
As a method for forming the fingerprint prevention treatment layer 81, a vacuum deposition method (dry method) in which a fluorine-containing organic compound or the like is evaporated in a vacuum chamber and adhered to the surface of the antireflection layer, or a fluorine-containing organic compound or the like is used as an organic solvent. A method (wet method) or the like that is dissolved in the solution, adjusted to a predetermined concentration, and applied to the surface of the antireflection layer can be used.

As a dry method, an ion beam assisted vapor deposition method, an ion plate method, a sputtering method, a plasma CVD method and the like can be appropriately selected from a spin coating method, a dip coating method, a casting method, a slit coating method, a spray method, and the like. . Both dry and wet methods can be used.

As a method for forming a fluorine-containing organosilicon compound film, a composition of a silane coupling agent having a perfluoroalkyl group; a fluoroalkyl group such as a fluoroalkyl group containing a perfluoro (polyoxyalkylene) chain is spin-coated. Method, dip coating method, casting method, slit coating method, spray coating method, etc., followed by heat treatment, or vapor deposition of a fluorine-containing organosilicon compound, followed by heat treatment, vacuum deposition method, etc. It is done. In addition, the density | concentration of the solution in the case of apply | coating by the spray coat method has preferable 0.15 mass% or less, and 0.1 mass% or less is still more preferable.
The formation of the fluorine-containing organosilicon compound film is preferably carried out using a film-forming composition containing a fluorine-containing hydrolyzable silicon compound.
The above is description about the example of the manufacturing method of the cover glass 1. FIG.

[Function and effect of cover glass 1]
The cover glass 1 has a triboelectric charge amount of 0 kV or less and −1.5 kV or more on the surface of the anti-fingerprint treatment layer 81. Therefore, it is difficult to be triboelectrically charged even if a user's finger touches the surface, and is incorporated in a display device. In this case, white turbidity caused by static electricity can be prevented.
Since the cover glass 1 suppresses frictional charging by the physical properties of the chemically strengthened glass 2, it is not necessary to provide a conductive layer, and white turbidity can be prevented without increasing the thickness and man-hour.
The depth DOL of the compressive stress layers 25 and 32 of the chemically strengthened glass 2 of the cover glass 1 is 60 μm or more. Therefore, when an impact is applied from the outside, the deformation due to the impact is hardly transmitted to the tensile stress layer, and the impact resistance of the glass surface can be improved.

Of the oxide components constituting the tensile stress layer of the cover glass 1, the concentration of Li ₂ O, Na ₂ O, K ₂ O, which does not contribute to the formation of the glass skeleton and has high mobility and discharges in combination with static electricity When the total is A mol% and the concentration of Al ₂ O ₃ is B mol%, it is preferable that A is 14.5 or more and A × B is 120 or more. Alternatively, among the oxide components constituting the tensile stress layer, when the total concentration of Li ₂ O, Na ₂ O, and K ₂ O is C mass% and the concentration of Al ₂ O ₃ is D mass%, C is 11 or more and C × D is preferably 140 or more.
In such a case, the surface contains a certain amount or more of Li ₂ O, Na ₂ O, K ₂ O that does not contribute to the formation of the glass skeleton, and has a high mobility and is statically discharged in combination with static electricity. Even if it contacts, it is hard to be frictionally charged.
Furthermore, it contributes to skeletal formation, and _Li 2 _O, for containing Na 2 O, _Al 2 close to the _{K 2} O _{O 3} also a certain amount or _{_{more, Li 2 O, Na 2 O}} , K 2 O is entered into between the networks Extend the distance with. Therefore, Li ₂ O, Na ₂ O, and K ₂ O are more easily moved, and even if the user's finger or the like comes into contact with the surface, it is less likely to be frictionally charged.

Of the oxide components constituting the tensile stress layer of the chemically strengthened glass 2, the total concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ and P ₂ O ₅ is 81 mol% or less (or 82 mass% or less). In this case, the concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ , which is a component that contributes to the formation of a glass skeleton and has a high mobility and a weak effect of static elimination combined with static electricity, is constant. Since it is suppressed to the following, even if a user's finger or the like comes into contact with the surface, it is more difficult to be frictionally charged.

[Modification]
The present invention is not limited to the above embodiment, and various improvements and design changes can be made without departing from the scope of the present invention. Specific procedures, structures, and the like in carrying out the present invention may be other structures or the like as long as the object of the present invention can be achieved.

The shape of the chemically strengthened glass 2 may be not only a plate having only a flat surface but also a plate having at least a curved surface and a plate having a recess. For example, as shown in FIG. 2, the chemically strengthened glass 2 may be a bent glass. By using the bent glass, even if the counterpart member to which the cover glass 1 is attached has a bent shape, there is no possibility that the mounting accuracy will be lowered.
The thickness of the chemically strengthened glass 2 is preferably 0.5 mm or more. If it is glass provided with the thickness of 0.5 mm or more, there exists an advantage which can obtain the cover glass 1 which has high intensity | strength and favorable texture. The thickness is more preferably 0.7 mm or more. When used in an in-vehicle display device, the thickness is preferably 1.1 mm or more in order to ensure impact resistance that can withstand a head impact test. From the viewpoint of securing light weight and ensuring transmittance, it is preferably 5 mm or less, and more preferably 3 mm or less.
The planar shape of the chemically strengthened glass 2 is not particularly limited. Area not also particularly limited in the first major surface 21 and second major surface 22 but, for example 5000 mm ² ~ 50,000 mm ² about.

As shown in FIG. 3, at least one of the first main surface 21 and the second main surface 22 of the chemically strengthened glass 2 is anti-glare treated (AG treatment) as a functional layer 3. You may provide at least one of the glare layer or the antireflection layer which performed the antireflection process (AR process).
When the first main surface 21 is provided with an antiglare layer or an antireflection layer, an antiglare function layer or an antireflection layer is provided between the chemically strengthened glass 2 and the anti-fingerprint treatment layer 81.
By providing an anti-glare layer as the functional layer 3, it is possible to scatter light incident from the first main surface 21 side and blur the reflection due to the incident light.
Examples of a method for imparting antiglare properties include a method of forming an uneven shape on the first main surface 21 of the chemically strengthened glass 2. Either an antiglare layer may be provided after chemical strengthening, or a chemical strengthening treatment may be performed after providing the antiglare layer.

As a method for forming the uneven shape, a known method can be applied. A method of forming an etching layer by chemically or physically surface-treating the first main surface 21 of the chemically strengthened glass 2 to form an uneven shape with a desired surface roughness, or a coating such as an antiglare film A method of applying a layer can be used.
When the antiglare layer is an etching layer, it is advantageous in that it is not necessary to separately coat an antiglare material. When the antiglare layer is a coating layer, it is advantageous in that the antiglare property can be easily controlled by selecting a material.

As a method of chemically anti-glare treatment, frost treatment can be mentioned. The frost treatment can be realized, for example, by immersing a glass substrate as an object to be treated in a mixed solution of hydrogen fluoride and ammonium fluoride. As a method of physically performing the antiglare treatment, for example, a sand blast treatment in which crystalline silicon dioxide powder, silicon carbide powder or the like is sprayed onto the main surface of the glass substrate with pressurized air, crystalline silicon dioxide powder, silicon carbide powder, or the like. For example, a method of rubbing with a brush moistened with water can be used.

The surface of the antiglare layer preferably has a surface roughness (root mean square roughness, RMS) of 0.01 μm to 0.5 μm. The surface roughness (RMS) of the surface of the antiglare layer is more preferably 0.01 μm to 0.3 μm, further preferably 0.02 μm to 0.2 μm. By setting the surface roughness (RMS) of the surface of the antiglare layer within the above range, the haze value of the cover glass 1 can be adjusted to 1% to 30%. The haze value is a value defined by JIS K 7136 (2000).

By providing an antireflection layer as the functional layer 3, reflection of light incident from the first main surface 21 side can be prevented, and reflection due to incident light can be prevented. Examples of the antireflection layer include the following.
(1) An antireflection layer having a multilayer structure in which a low refractive index layer having a relatively low refractive index and a high refractive index layer having a relatively high refractive index are alternately laminated.
(2) An antireflection layer comprising a low refractive index layer having a refractive index lower than that of the chemically strengthened glass 2.

The antireflection layer (1) has a structure in which a high refractive index layer having a refractive index of light of 1.9 nm or more and a low refractive index layer having a refractive index of light having a wavelength of 550 nm of 1.6 or less are laminated. Is preferably provided. When the antireflection layer has a structure in which a high refractive index layer and a low refractive index layer are stacked, reflection of visible light can be more reliably prevented.

The number of the high refractive index layer and the low refractive index layer in the antireflection layer of (1) may be one each, or may be two or more. When each of the high refractive index layer and the low refractive index layer is included, the antireflection layer is formed by laminating the high refractive index layer and the low refractive index layer in this order on the first main surface 21 of the chemically strengthened glass 2. It is preferable. When two or more high refractive index layers and low refractive index layers are included, the antireflection layer is preferably a laminate in which high refractive index layers and low refractive index layers are alternately stacked. From the viewpoint of productivity, the laminate is preferably a laminate of 2 to 8 layers as a whole, more preferably a laminate of 2 to 6 layers. Moreover, you may add the layer in the range which does not impair an optical characteristic. For example, in order to prevent Na diffusion from the glass plate, a SiO ₂ film may be inserted between the glass and the first layer.

The material constituting the high refractive index layer and the low refractive index layer is not particularly limited, and can be selected in consideration of the required degree of antireflection and productivity. Examples of the material constituting the high refractive index layer include niobium oxide (Nb ₂ O ₅ ), titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), tantalum oxide (Ta ₂ O ₅ ), and silicon nitride (SiN). Etc. One or more selected from these materials can be preferably used. Examples of the material constituting the low refractive index layer include silicon oxide (particularly silicon dioxide SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), magnesium fluoride (MgF ₂ ), and a mixed oxide of Si and Sn. And a material containing a mixed oxide of Si and Zr, a material containing a mixed oxide of Si and Al, and the like. One or more selected from these materials can be preferably used.

In the antireflection layer of (2), the refractive index of the low refractive index layer is set according to the refractive index of the chemically strengthened glass 2, and is preferably 1.1 to 1.5, more preferably 1.1 to 1.4. preferable.

The antireflection layer of (2) is a method of directly forming an inorganic thin film on the surface, a method of surface treatment by a technique such as etching, a dry method such as a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method, It can be suitably formed by vacuum vapor deposition or sputtering, which is a kind of physical vapor deposition.

The thickness of the antireflection layer is preferably 90 nm to 500 nm. Setting the thickness of the antireflection layer to 90 nm or more is preferable because reflection of external light can be effectively suppressed.

In the CIE (International Commission on Illumination) color difference formula, the antireflection layer is preferably such that the reflective color of the cover glass with a film is a ^* of −6 to 1 and b ^* of −8 to 1.
When the a ^{* of the} antireflection layer is -6 to 1 and the b ^* is -8 to 1, the antireflection layer is not likely to be colored in a dangerous color (warning color), and the color of the antireflection layer is conspicuous. Can be prevented.
When the antireflection layer and the fingerprint prevention treatment layer 81 are formed directly on the glass without forming the antiglare layer, the cover glass 1 is reflected after the fingerprint prevention treatment layer 81 is removed by corona treatment or plasma treatment. The surface roughness measured on the surface of the prevention treatment layer is preferably less than 1 nm in Ra. If the contact angle of water on the surface is about 20 ° or less, it can be determined that the anti-fingerprint treatment layer has been removed. When the surface roughness Ra after removing the outermost fingerprint prevention treatment layer 81 is less than 1 nm, high scratch resistance can be realized. More preferably, it is 0.3 nm to 0.6 nm, and particularly preferably 0.3 nm to 0.5 nm.
The surface roughness Ra can be measured, for example, in the DFM mode of a scanning probe microscope SPI3800N manufactured by Seiko Instruments Inc.

As shown in FIG. 4B, the cover glass 1 may include a light shielding layer 31 provided on the second main surface 22. The light shielding layer 31 is a layer that shields visible light. Specifically, the light shielding layer 31 is, for example, a layer having a luminous transmittance of 50% or less for light with a wavelength of 380 nm to 780 nm. By providing the light shielding layer 31, it is possible to conceal the wiring on the display device side or conceal the illumination light of the backlight to prevent the illumination light from leaking from the periphery of the display device.
The second main surface 22 and the chamfered portion 24 provided with the light shielding layer 31 may be subjected to a primer treatment, an etching treatment, or the like in order to improve the adhesion with the light shielding layer 31.

A method for providing the light shielding layer 31 is not particularly limited, and examples thereof include a method for providing ink by printing by a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, a screen method, an ink jet method, or the like. Considering the easy difference in thickness control, the screen method is preferable.
The ink used for the light shielding layer 31 may be inorganic or organic. Examples of the inorganic ink include one or more selected from SiO ₂ , ZnO, B ₂ O ₃ , Bi ₂ O ₃ , Li ₂ O, Na ₂ O and K ₂ O, CuO, Al ₂ O ₃ , ZrO _2, SnO ₂ and one or more selected from CeO _2, may be a composition consisting of _Fe 2 _{O 3} and TiO _2.

As the organic ink, various printing materials in which a resin is dissolved in a solvent can be used. For example, the resin includes acrylic resin, urethane resin, epoxy resin, polyester resin, polyamide resin, vinyl acetate resin, phenol resin, olefin, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, natural rubber, styrene-butadiene copolymer At least one or more selected from the group consisting of a resin such as a polymer, an acrylonitrile-butadiene copolymer, a polyester polyol, and a polyether polyurethane polyol may be selected and used. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents may be used. For example, isopropyl alcohol, methanol, ethanol or the like can be used as the alcohol, ethyl acetate can be used as the ester, and methyl ethyl ketone can be used as the ketone. As the aromatic hydrocarbon solvent, toluene, xylene, Solvesso (registered trademark) 100, Solvesso (registered trademark) 150 or the like can be used, and as the aliphatic hydrocarbon solvent, hexane or the like can be used. These are given as examples, and various other printing materials can be used. The organic printing material can be applied to the chemically strengthened glass 2 and then the solvent is evaporated to form the resin light-shielding layer 31. The ink used for the light shielding layer 31 may be a thermosetting ink that can be cured by heating or a UV curable ink, and is not particularly limited.

The ink used for the light shielding layer 31 may contain a colorant. As the colorant, for example, when the light shielding layer 31 is black, a black colorant such as carbon black can be used. In addition, a colorant having an appropriate color can be used according to a desired color.
The light shielding layer 31 may be laminated as many times as desired, and different inks may be used for printing. Further, the light shielding layer 31 may be printed not only on the second main surface 22 but also on the first main surface 21 or on the end surface.
When the light shielding layer 31 is laminated a desired number of times, different inks may be used for each layer. For example, when the user looks at the cover glass 1 from the first main surface 21 side and wants the light shielding layer 31 to appear white, the first layer is printed in white, and then the second layer is printed in black. Print it out. Thus, when the user views the light shielding layer 31 from the first main surface 21 side, the white light shielding layer 31 that suppresses the so-called “translucency” related to the visibility of the back surface of the light shielding layer 31 can be formed.

The planar shape of the light shielding layer 31 is a frame shape in FIG. 4, and the inside of the frame constitutes the display region 4, but is not a frame shape, but a linear shape along one side of the second main surface 22, two continuous sides L shape along the two, or two straight lines along the two opposite sides. When the second main surface 22 is a polygon other than a quadrangle, a circle, or an irregular shape, the light shielding layer 31 has a frame shape corresponding to these shapes, a linear shape along one side of the polygon, or an arc shape along a part of the circle. But you can.
When the cover glass 1 is used for a display device, the light shielding layer 31 preferably has a color corresponding to the color when the display device is not displayed. For example, when the non-display color is black, it is desirable that the light shielding layer 31 is also black.

When the cover glass 1 includes the light shielding layer 31, the light shielding layer 31 may have an opening 33 as shown in FIG. 5, and the infrared transmission layer having a higher infrared transmittance than the light shielding layer 31 is provided in the opening 33. 35 is preferably provided. By providing the opening 33 in a part of the light shielding layer 31 and providing the infrared transmission layer 35, the infrared sensor can be provided on the back side of the light shielding layer 31, and the infrared transmission layer 35 can be made inconspicuous.
The ink forming the infrared transmission layer 35 may be inorganic or organic. Examples of the pigment contained in the inorganic ink include one or more selected from SiO ₂ , ZnO, B ₂ O ₃ , Bi ₂ O ₃ , Li ₂ O, Na ₂ O, and K ₂ O, CuO, and Al _2. It may be a composition comprising at least one selected from O ₃ , ZrO ₂ , SnO ₂ and CeO ₂ , Fe ₂ O ₃ and TiO ₂ .

As the organic ink, various printing materials in which a resin and a pigment are dissolved in a solvent can be used. For example, the resin includes acrylic resin, urethane resin, epoxy resin, polyester resin, polyamide resin, vinyl acetate resin, phenol resin, olefin, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, natural rubber, styrene-butadiene copolymer At least one or more selected from the group consisting of a resin such as a polymer, an acrylonitrile-butadiene copolymer, a polyester polyol, and a polyether polyurethane polyol may be selected and used. As the solvent, water, alcohols, esters, ketones, aromatic hydrocarbon solvents, and aliphatic hydrocarbon solvents may be used. For example, isopropyl alcohol, methanol, ethanol or the like can be used as the alcohol, ethyl acetate can be used as the ester, and methyl ethyl ketone can be used as the ketone. As the aromatic hydrocarbon solvent, toluene, xylene, Solvesso (registered trademark) 100, Solvesso (registered trademark) 150 or the like can be used, and as the aliphatic hydrocarbon solvent, hexane or the like can be used. These are given as examples, and various other printing materials can be used. The organic printing material can be applied to the chemically strengthened glass 2, and then the solvent can be evaporated to form the resin infrared transmission layer 35. A thermosetting ink that can be cured by heating or a UV curable ink may be used, and there is no particular limitation.

The ink used for the infrared transmission layer 35 may contain a pigment. As the pigment, for example, when the infrared transmitting layer 35 is black, a black pigment such as carbon black can be used. In addition, a pigment having an appropriate color can be used according to a desired color.

The content ratio of the pigment in the infrared transmission layer 35 can be freely changed according to desired optical characteristics. The content ratio, which is the ratio of the pigment content to the total mass of the infrared transmitting layer 35, is preferably 0.01% by mass to 10% by mass. The content ratio can be realized by adjusting the content ratio of the infrared transmitting material with respect to the entire mass of the ink.

The ink forming the infrared transmission layer 35 includes a pigment having infrared transmission ability in a photo-curable resin or a thermosetting resin. As the pigment, either an inorganic pigment or an organic pigment can be used. Examples of inorganic pigments include iron oxide, titanium oxide, and complex oxides. Examples of the organic pigment include metal complex pigments such as phthalocyanine pigments, anthraquinone pigments, and azo pigments. The color of the infrared transmission layer 35 is preferably the same as that of the light shielding layer 31. When the light shielding layer 31 is black, the infrared transmission layer 35 is also preferably black.

The method for forming the infrared transmitting layer 35 is not particularly limited, and examples thereof include a bar coating method, a reverse coating method, a gravure coating method, a die coating method, a roll coating method, a screen method, and an ink jet method. In consideration of the continuity of the manufacturing method, the same formation method as the light shielding layer 31 is preferable.

The cover glass 1 of the present invention can be used, for example, as a cover member for a display device such as a panel display such as a liquid crystal display, an in-vehicle information device, or a portable device. By using the cover glass 1 of the present invention for the cover for a display device, it is possible to prevent white turbidity when using the touch sensor while protecting the object.
Furthermore, the cover glass 1 of the present invention can be applied to the surface of the cover glass when a panel display such as a liquid crystal display or an organic EL display, an in-vehicle information device, or a portable device is bonded. Since the cover glass, which is generated when the laminate to be applied is peeled off, is suppressed from being charged, foreign matter adsorption due to charging can be suppressed.

Here, an example of a display device including the cover glass 1 will be described with reference to FIG. Here, an in-cell IPS (In Plane Switching) liquid crystal display device is illustrated.
The display device 10 illustrated in FIG. 6 includes a frame 5. The frame 5 includes a bottom 51, a side wall 52 that intersects the bottom 51, and an opening 53 that faces the bottom 51. The liquid crystal module 6 is disposed in a space surrounded by the bottom 51 and the side wall 52. The liquid crystal module 6 includes a backlight 61 disposed on the bottom 51 side, and a liquid crystal panel 62 (display panel) disposed on the backlight 61. The liquid crystal panel 62 includes an IPS liquid crystal and is an in-cell type in which an element having a touch function is embedded in the liquid crystal element.
Further, the cover glass 1 is provided at the upper end of the frame 5 so that the second main surface 22 faces the liquid crystal module 6 side. The cover glass 1 is bonded to the frame 5 and the liquid crystal module 6 via an adhesive layer 7 provided on the upper end surface of the opening 53 and the side wall 52.

The adhesive layer 7 is preferably transparent and has a small refractive index difference from the chemically strengthened glass 2.
Examples of the adhesive layer 7 include a layer made of a transparent resin obtained by curing a liquid curable resin composition. As a curable resin composition, a photocurable resin composition, a thermosetting resin composition, etc. are mentioned, for example, Among these, the photocurable resin composition containing a curable compound and a photoinitiator is preferable. The curable resin composition is applied using a method such as a die coating method or a roll coating method to form a curable resin composition film.
The adhesive layer 7 may be an OCA film (OCA tape). In this case, an OCA film may be bonded to the second main surface 22 side of the cover glass 1.
The thickness of the adhesive layer 7 is preferably 5 μm or more and 400 μm or less, and more preferably 50 μm or more and 200 μm or less. The storage shear modulus of the adhesive layer 7 is preferably 5 kPa to 5 MPa, and more preferably 1 MPa to 5 MPa.

In manufacturing the display device 10, the assembly order is not particularly limited. For example, a structure in which the adhesive layer 7 is disposed on the cover glass 1 in advance may be prepared, disposed on the frame 5, and then the liquid crystal module 6 may be bonded.

Next, examples of the present invention will be described. The present invention is not limited to the following examples.
Cover glasses having various characteristics were produced, and the amount of charge and the degree of white turbidity when incorporated in the apparatus were determined. The specific procedure is as follows. Example 1 is an example, and Examples 2 to 6 are comparative examples.

(Example 1)
First, as the glass before chemical strengthening, the raw materials were prepared and melted so as to become a glass having the composition shown in Example 1 in Table 1, and poured out into a block of about 110 mm square, and then slowly cooled. A glass body was obtained. Then, it cut | disconnected and cut so that it might become a plate shape of length 100mm, width 100mm, and thickness 0.7mm.
Next, this glass was chemically strengthened. The chemical strengthening was performed by immersing in a 100 wt% sodium nitrate molten salt at a temperature of 450 ° C. for 3 hours and then immersing in a 100 wt% potassium nitrate molten salt at a temperature of 450 ° C. for 3 hours for chemical strengthening.
After the tempered glass was washed, a liquid obtained by diluting Afluid S-550 manufactured by Asahi Glass Co. to 0.1% by mass with fluorinated solvent Asahi Clin AC6000 manufactured by Asahi Glass Co., Ltd. as a fingerprint prevention treatment layer 81 on the surface was spray-coated. This was applied to form an anti-fingerprint treatment layer, and the cover glass of Example 1 was obtained. The film thickness of the fingerprint prevention treatment layer was 5 nm.
In addition, although the sum total of the composition (mol%, mass%) of each glass of Example 1 to Example 6 in Table 1 may not be 100, it is a result of rounding off each value, and is described in the claims. Does not affect the concentration calculation.
The following evaluation was performed on the produced cover glass of Example 1.
<CS, DOL>
Using a glass surface stress meter device (FSM-6000LE) manufactured by Orihara Manufacturing Co., Ltd. and a measuring machine SLP1000 manufactured by Orihara Manufacturing Co., Ltd. using scattered light photoelasticity, the stress distribution in the thickness direction of the glass was measured, The stress value was defined as surface compressive stress CS. The glass depth at which the stress value becomes 0 MPa in the glass was defined as the compressive stress depth DOL.
<CT>
CT was approximately obtained by the relation CT = (CS × DOL) / (t−2 × DOL).
<Friction charge amount>
The triboelectric charge amount was determined by the D method (triboelectric charge decay measurement method) described in JIS L1094: 2014 using a friction band voltage decay measurement device manufactured by INTEC.
<White turbidity>
The obtained cover glass is incorporated into an in-cell type IPS liquid crystal display device, and with the power turned on, the surface of the cover glass is touched with a finger, and a distance of 10 cm is made 10 reciprocations at a speed of 1 reciprocation per second. It moved and the presence or absence of clouding was confirmed visually. Those that became white turbid were judged as “present”, and those that did not become white turbid were judged as “none”.

(Example 2)
As a glass before chemical strengthening, a glass having a composition shown in Example 2 in Table 1 was produced by a float process to obtain a 0.7 mm glass plate, and it was added to a 100 wt% potassium nitrate molten salt at 420 ° C. for 8 hours. A cover glass of Example 2 was produced under the same conditions as Example 1 except that chemical strengthening was performed by immersion.

(Example 3)
Except that the glass having the composition shown in Example 3 in Table 1 was used as the glass before chemical strengthening, and that chemical strengthening was performed by immersing in 100 wt% potassium nitrate molten salt at 425 ° C. for 6 hours. A cover glass of Example 3 was produced under the same conditions as in Example 1.

(Example 4)
Example 1 except that the glass having the composition shown in Example 4 in Table 1 was used as the glass before chemical strengthening, and that the glass was chemically strengthened by immersion in 100 wt% potassium nitrate molten salt at a temperature of 425 ° C. for 6 hours. A cover glass of Example 4 was produced under the same conditions as in Example 1.

(Example 5)
As a glass before chemical strengthening, raw materials were prepared and melted so as to become a glass having the composition shown in Example 5 in Table 1, and a glass block was obtained. Also, a 100 wt% sodium nitrate molten salt at a temperature of 450 ° C. The cover glass of Example 5 was produced under the same conditions as in Example 1 except that it was immersed in 100 wt% potassium nitrate molten salt at a temperature of 425 ° C. for 1.5 hours for chemical strengthening.

(Example 6)
A cover glass of Example 6 was produced under the same conditions as Example 1 except that the glass having the composition shown in Example 6 in Table 1 was used as the glass after chemical strengthening.
The results are shown in Table 1.

As shown in Table 1, in Example 1, the triboelectric charge amount is 0 kV or less, −1.5 kV or more, the depth DOL of the compressive stress layer is 60 μm or more, and among the total alkali metals contained in the tensile stress layer, , Li had the largest number of moles, and no clouding occurred.
In Examples 2 to 4, since the DOL was less than 60 μm, the impact resistance of the glass surface was inferior, making it unsuitable as a cover glass.
In Examples 4 to 6, the triboelectric charge amount was less than −1.5 kV, and white turbidity occurred.
In Example 1, CS was 800 to 1000 MPa, and CT was about 60 MPa.
In Example 1, A was 14.5 mol or more, and A × B was 120 or more.
In Example 1, the total concentration of SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , and P ₂ O ₅ was 81 mol% or less.

From the above results, the triboelectric charge amount is 0 kV or less, −1.5 kV or more, the depth DOL of the compressive stress layer is 60 μm or more, and among all the alkali metals contained in the tensile stress layer, the number of moles of Li is It has been found that by using the largest composition, a cover glass that can prevent white turbidity and is excellent in impact resistance can be obtained.

Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on Feb. 16, 2018 (Japanese Patent Application No. 2018-26236), which is incorporated by reference in its entirety. Also, all references cited herein are incorporated as a whole.

DESCRIPTION OF SYMBOLS 1 ... Cover glass, 2 ... Chemically tempered glass, 3 ... Functional layer, 4 ... Display area, 5 ... Frame, 6 ... Liquid crystal module, 7 ... Adhesive layer, 10 ... Display apparatus, 21 ... 1st main surface, 22 ... 2nd main surface, 23 ... end face, 24 ... chamfered portion, 25 ... compressive stress layer, 27 ... tensile stress layer, 31 ... light shielding layer, 32 ... compressive stress layer, 33 ... opening, 35 ... infrared ray transmitting layer, 51 ... Bottom, 52 ... Side wall, 53 ... Opening, 61 ... Backlight, 62 ... Liquid crystal panel, 81 ... Anti-fingerprint treatment layer

Claims

A chemically strengthened glass comprising a first main surface and a second main surface;
An anti-fingerprint treatment layer provided on the first main surface;
With
The chemically strengthened glass is
Of all alkali metals contained in the tensile stress layer, the number of moles of Li is the most,
The depth DOL of the compressive stress layer is 60 μm or more,
A cover glass characterized in that the triboelectric charge amount on the surface of the anti-fingerprint treatment layer is 0 kV or less and −1.5 kV or more according to the D method described in JIS L1094: 2014.
The chemically strengthened glass is
Among the oxide components constituting the tensile stress layer, when the total concentration of Li 2 O, Na 2 O, and K 2 O is A mol% and the concentration of Al 2 O 3 is B mol%, A is 14. The cover glass according to claim 1, wherein 5 or more and A × B is 120 or more.
The chemically strengthened glass is
Among oxide components constituting the tensile stress layer, when the total concentration of Li 2 O, Na 2 O, and K 2 O is C mass% and the concentration of Al 2 O 3 is D mass%, C is 11 or more. The cover glass according to claim 1, wherein C × D is 140 or more.
The chemically strengthened glass is
The cover according to claim 1 or 2, wherein the total concentration of SiO 2 , Al 2 O 3 , B 2 O 3 , and P 2 O 5 among the oxide components constituting the tensile stress layer is 81 mol% or less. Glass.
The chemically strengthened glass is
The cover according to claim 1 or 2, wherein the total concentration of SiO 2 , Al 2 O 3 , B 2 O 3 , and P 2 O 5 among the oxide components constituting the tensile stress layer is 82% by mass or less. Glass.
The cover glass according to any one of claims 1 to 5, comprising at least one of an antiglare functional layer or an antireflection layer provided between the chemically strengthened glass and the anti-fingerprint treatment layer.
The cover glass according to any one of claims 1 to 6, further comprising a light shielding layer provided on the second main surface.
The light shielding layer has an opening;
The cover glass according to claim 7, wherein the opening is provided with an infrared transmission layer having an infrared transmission rate higher than that of the light shielding layer.
The cover glass according to any one of claims 1 to 8, wherein the chemically strengthened glass is a bent glass.
The antiglare layer is provided between the first main surface and the fingerprint prevention treatment layer, and the surface roughness of the antiglare layer is 0.01 μm to 0.5 μm in Ra. The cover glass according to one item.
An in-cell IPS liquid crystal display device comprising the cover glass according to any one of claims 1 to 10.